Like any lucrative new market, the Clean Development Mechanism inspires creativity.

Take Nigeria, for example.

If the U.N. oversight board approves, the Nigerian government stands to reap hundreds of millions of dollars' worth of emissions credits for shutting down a huge source of carbon dioxide _ its burning of natural gas pumped up with petroleum at its Ovade Ogharefe oil field.

It could then sell the credits to industrial nations lagging in cutting their own global-warming emissions, while selling the methane and other gases to local or international energy companies.

That's the plan.

The problem, according to environmentalists, is that gas flaring, an air pollutant in Nigeria's oil belt, already has been ordered halted in another location by a Nigerian court, which ruled last November it was a "gross violation" of local people's constitutionally guaranteed right to life and dignity.

It would be "outrageous" for Nigeria to make huge profits off halting an activity already held to be "illegal, unconstitutional and a human rights violation," Lawrence C. Lohmann, of the British environmental group Corner House, said in a formal objection to the U.N. application.

Paul Parks, a director of ECON Carbon, the Norwegian firm that developed the CDM proposal for Nigeria, said the Nigerian government is appealing the court ruling, which he also said doesn't apply directly to Ovade Ogharefe.

"I also think gas flaring should be ended, and the Clean Development Mechanism is an appropriate mechanism for doing that," Parks said.